Piano.



ANTON KRIEGHOFF, OF BOSTON, MASSACI-I COMPANY, OF BOSTON, MASSACHUSETTS USETTS, ASSIGNOR TO ANTON KRIEGHOFF A CORPORATION OF MASSACHUSETTS.

PIANO.

Specification of Letters Patent.

Patented Apr. 2, 1918.

Application filed May 13, 1915. Serial No. 27,927.

To all whom it may concern:

Be it known thatl, ANTON Knmeuorr, a citizen of the United. States, and resident of Boston, county of Suffolk, State of Massachusetts, have invented an improvement in Pianos, of whichthe following description, in connection with the accompanying drawing, is a specification, like characters on the drawingrepresenting like parts.

The general purpose of this novel construction is to produce a piano in which the vibrating parts (particularly the sounding board) will be free to perform their functions without detracting from the structural stability and efiiciencyofthe frame necessary to withstand the tension imposed by the strings.

In this .novel construction there is employed a sounding-board from which have been eliminated all of the usual wooden bridges. The string plate, which is otherwise of the present general type, has a section thinner than most portions of the plate. This section is therefore relatively flexible and. adapted the more freely to take up, and communicate vibratory energy imparted thereto by the strings which are provided with bridges on this section. Sound posts or transmitters connect this section to the sounding-board and serve to communicate the vibrations of the section to the soundingboard. 1

This section, as shown inthe embodiment disclosed herein, is preferably an integral part-of the metal string plate. Hitch pins for the treble strings are placed upon the sectionand a narrow bearing or bridge is formed thereon for the treble strings. The hitch pins for the bass strings are placed upon the string plate-while a bridge therefor is provided upon this'flexible section. Hence it is obvious that in this embodiment both treble and bassstrings are in contact with this flexible section.

It is readily apparent that the inventive idea here disclosed may be embodied in widely variant piano structures as also in other musical instruments whether the string actuating means be mechanical, elec trical or manual.

An. object of thisin-vention is to improve the tonal qualities of musical instruments by increasing the resonance of the soundingboard through the elimination of'bridges thereon.

ther objects of the invention will more fully appear from the following description and the accompanying drawings and will be pointed out in the annexed claims.

Figure 1 is a plan view of a piano string plate and sounding board embodying the invention Fig. 2 is a section on the line 22, Fig. 1;

Fig. 3 is a section on the line 33, Fig. 1;

Fig. i is a sectional detailof one of the transmitters Fig. 5 is a sectional detailof a modified form of transmitter.

The selected embodiment of the invention illustrated is of a structure employed in an instrument of the upright type, but it is obvious that with slight changes, it may be employed in pianos of the grand or other type, or in similar musical instruments.

The cast metal string plate 1 has secured thereto, as in the usual construction, the sounding-board 2 of the well-known type.

he string plate is reinforced by transverse braces 4 to insure rigidity under the cnormous strain induced by the piano strings when in position under theusual tension. In place of the ordinary treble hitch section, this string plate is provided with a thinner and relativelymore fieXiblesectiO1r3. As shown, it is preferalily made in the form of an elongated platelike sect-ion free at its longer edges and integrally cast at its ends. This section '3 may, of course, be made of any suitably vibratory substance. The section 3, save at its integrally cast ends, does not bear upon or come into contact with other parts of the string plate. The elongated section 3 is flat and, as clearly disclosed in Fig. l, is preferably curved along the line of its longest dimension. This longitudinal curve affords opportunity to position'bridging means for the strings on the section to accommodate the varying lengths of the strings as shown. The vertical braces l'have. offset portions 5 which pass behind and do not touch the section 3 or impede in any mannerits free vibration.

The vibrations which are set up in th flexible section are communicated to the sounding-board 2 by means of a plurality of transmitters.

These transmitters consist each of a metallic post 6 passed through the section 3 and received in threaded engagement with the wooden sounding-board. A block of wood 7 is aflixed to the rear face of the sounding-board opposite each post to receive the screw-threaded end of the post. The other end of the post, extending through the section 3, has threaded thereon two nuts 8 turned tightly against the front and rear faces respectively of the section.

A modification of the transmitter is shown in Fig. 5. In this form there are a plurality of lugs 9 integrally cast on the rear face of the section which extend a distance so that their ends impinge upon the front face of the sounding-board. These lugs have each a central threaded aperture 10 in which is received a set screw 11. The set screw passes through the soundingboard and is received in threaded engagement with the lug aperture. The washers 12 are carried by the set screw and are firmly pressed against the front and rear faces of the sounding-board.

The hitch pins 13 for the treble strin s 14 are secured adjacent the upper edge 0 the section 3. A rib 15 preferably cast integral with this section, extends substantially its length. This rib is positioned adjacent the upper edge of the section and provides a bearing or bridge for the strings leading from the hitch pins 13 over the soundingboard 2, to the usual upper bearing 16 under the pressure bar 17, to the wrest pins 18. These wrest pins 18 in accordance with the usual construction are passed through the metal string plate 1 and are embedded in the wrest plank 19.

The hitch pins 20 for the bass strings 21 are mounted on the string plate. A hearing or bridge for the bass strings is preferably also provided on the flexible section. As shown in Fig. 3, this bridge consists of a flange 22 which extends a short distance along the lower edge of the section. Bearing pins 23 are secured thereto and provide a bearing on the flexible section for the bass strings leading from their hitch pins over the section 3 and sounding-board to their respective wrest pins 18.

The portions of the treble strings which freely vibrate when struck by the usual hammers are those which are comprehended between the bearing points of the strings on the rib 15 of the flexible section 3 and the usual upper bearing 16 on the piano string plate. The similar freely vibratile portions of the bass strings are those which are comprehended between the bearing-pin flange 22 and the pins on the usual upper bass string bearing. The vibrations of the various strings are thus directly communicated to the flexible section by means of the treble and bass bearings or bridges. The section, which as conditions demand is made more or less flexible and resilient and free to vibrate throughout its area, readily receives and takes up the string vibrations,

v'ibratory energy imparted to the section is connnunicated to the sounding-board by means of the transmitters so located with reference to the section as efliciently to convey the sound vibrations. The soundingboard, energized through the medium of these transmitters and being without longitudinal bridges or braces thereon, vibrates freely substantially throughout its area.

This invention removes the usual bridges from the sounding-board and places them on the string plate and leaves the soundingboard entirely free therefrom. And, in the employment of this flexible section, vibrantly energized through the of the string bearings thereon, and, directl connected to a bridgeless sounding-board more perfect, intensified and full tones are derived. Further, the production cost is lowered, the'construction is simpler, is composed of fewer parts and the structural efficiency of the assembled whole is augmented. It is to be understood that the construction disclosed herein is illustrative but not restrictive and that the same may be modified within the meaning and scope of the claims which follow.

that I claim is:

1. In a musical instrument, a string plate, a sounding board, strings, the string plate having an elongated platelike section more flexible than the remainder of the stringplate, means by which the vibrations of the strings may be communicated to said section, and means for communicating the vibrations of said section to the sounding-board.

2. In a musical instrument, a string plate, a soundingboard, the string plate having an elongated platelike section more flexible than the remainder of the string-plate, strings, bridges for the strings on said section by which the vibrations of the strings may be communicated to said section, and means for communicating the vibrations of said section to the sounding-board.

3. In a musical instrument, a string-plate, a sounding-board, strings, the string plate having an elongated section free at its longer edges and integrally attached at its ends, bridges on said section for the strings whereby the vibrations of the strings may be communicated to said section, and means for communicating the vibrations of the section to the sounding-board.

4. In a musical instrument, a string plate, a sounding-board, strings, the string plate having a relatively flexible elongated section integrally attached at its ends, said section intermediary having integral bridges for the strings whereby the vibrations of the strings may be communicated to said section, and means for communicating the vibrations of the section to the sounding-board.

5. In a musical instrument, a string plate, a sounding-board, strings, the string plate having a platelike section more flexible than the remainder of the string plate, hitch pins for treble strings on said section, hitch pins on the string plate for the bass strings, bridges on said section for all said strings whereby the vibrations of the strings may be communicated to said section, and means for communicating the vibrations of the section to the sounding-board.

6. In a musical instrument, a string plate, a sounding-board, strings, the string plate having an elongated section more flexible than the remainder of the string-plate, marginal ribs longitudinally disposed on said Copies of this patent may be obtained for five cents each, by addressing section, said section being longitudinally curved and said ribs providing bridges for the strings to communicate the string vibrations to said section, and means for communicating the vibrations of the section to the sounding-board.

7. In a musical instrument, a string plate, a sounding-board, strings, the string plate having an elongated section more flexible than the remainder of the string-plate, means adjacent the longer edges of said section providing bridges for said strings to communicate; the string vibrations to said section, said section being longitudinally curved, and a plurality of instrumentalities fixedly connected to said section and said sounding-board to communicate the vibrations of the section to the sounding-board.

In testimony whereof, I have signed my name to this specification.

ANTON KRIEGHOFF.

the Commissioner of Patents,

Washington, I). C. 

